Automatic tension device.



L. LE R. ALMOND.

AUTOMATIG TENSION DEVIGE.

APPLICATION FILED MAR.10,1908. 1,007,837, Patented Nov. 7, 1 911.

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L.- LE R. ALMOND.

AUTOMATIC TENSION DEVICE.

APPLICATION FILED MAR.10,1908.

Patented Nov. 7, 1911.

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0LUMBM PLANDORAPH CO., WASHINGTON. D. C.

UNITED STATES PATENT OFFICE.

LESTER LE ROY ALMOND, OF TROY, NEW YORK, ASSIGNOR TO THE SINGER MANUFAC- TURING COMPANY, A CORPORATION OF NEW JERSEY.

AUTOMATIC TENSION DEVICE.

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To all whom it may concern" Be it known that I, LESTER L. ALMOND, a citizen of the United States, residing at 130 Congress street, city of Troy, in the county of Itensselaer and State of New York, have invented certain new and useful Improvements in Automatic Tension Devices, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement in sewing machines wherein a relative feeding movement is produced between the stitch-forming mechanism and the work in different directions, and it relates more particularly to machines in which the direction of feed of the work is reversed.

The invention has for its object to provide means for controlling the thread whereby the stitching may be laid uniformly for all conditions of relative feed between the stitch-forming mechanism and the work.

The invention consists essentially in an automatically acting thread controlling device adapted to vary the handling of the thread for changes in the relative feeding movements in different directions between the stitch-forming mechanism and the work.

\Vhile the present invention is obviously capable of embodiment in many classes of machines in which means are provided for producing relative feeding movements in different directions bet-ween the stitch-forming mechanism and the work, the improve mentis herein represented embodied in a straight buttonhole machine of the type in which the side stitching proceeds forwardly along one edge of the buttonhole slit and backwardly along the opposite side of the slit, the lead of the thread from the needle to the work in the stitching of one side of the buttonhole being directly from the needle-eye, and in the stitching of the opposite side of the buttonhole being wrapped around one side of the needle below the eye and extending to the work in the opposite direction from that in which it passes through the eye. Under these conditions, it is evident that the degree of tension upon that portion of the thread above the needleeye to set the stitch is much greater when the portion of thread beyond the needleseye is wound around the lower part of the needle than when it leads directly to the work; and therefore, in its preferred embodiment the Specification of Letters Patent.

Application filed March 10, 1908.

Patented Nov. '7, 1911.

Serial No. 420,153.

present improvement comprises an automatically acting thread controller, herein represented as an automatic tension device, operatlng to impose a stronger tension upon the thread when the lead of the latter from the needle-eye is around the needle than when it is directly away from the same.

The invention will be understood by reference to the accompanying drawings, in which Figure 1 is a rear side elevation and Fig. 2 a plan of the bracket-arm, and parts carried thereby, of a buttonhole cutting and stitching machine embodying the present improvement, and Fig. 3 a detached plan View of the work-clamp and its actuating means. Fig. 4; is a perspective view of the automatic tension device with the auxiliary tension disks open to release the thread, and Fig. 5 a similar view with the tension disks closed. Figs. 6 and 7 are views showing the lead of the thread from the eye of the needle during the advance and return feeding movements of the work in relation to the needle.

The present machine is constructed substantially as represented in the United States patent of E. B. Allen, No. 815,501, March 20, 1906, with the bed-plate 1 and overhanging bracket-arm 2 in which is journaled the mainshaft having the usual connections with the reciprocating needle-bar 3 carrying the needle 4 and mounted 'in the swing ing frame 5 to which the usual lateral movements are imparted by means specifically shown and described in the United States patent to E. B. Allen No. 806,231, dated December 5, 1905.

As in the Patent No. 806,231, before mentioned, the work-holder comprises the workclamp base-plate 6 which slides longitudinally in suitable guide-ways formed in the transverse plate 7 mounted for lateral sliding movement on the bed-plate 1. The slideplate 7 is provided centrally with a throatplate 8 having the usual needle-slot 9 and knife-slot 10. The upper clamping member comprises a foot-piece 11 whose workengaging edges are pressed normally upon the surface of the throat-plate 8, the footpiece being carried by the spaced arms 12 of a tilting lever fulcrumed at 13 upon a bearing bracket secured to the baseplate 6 and having a tail 14 adapted to be depressed by means of a suitable treadle-rod or cord to open the clamp in opposition to the spring 15surrounding the post 16 and normally acting to maintain the clamping foot in engagement with the throat-plate.

To communicate to the work-clamp the requisite longitudinal feeding movements, the feed-wheel 17, to which is imparted a step-by-step rotary movement by means of the clutch-lever 18 and connections with the main-shaft in a manner well-known, has in its upper face a cam-groove 19 entered by a pin or roller-stud 20 on the arm 21 of a clamp-feeding lever mounted upon a fixed fulcrum and having the curved and slotted arm 22 to which is adjustably connected one end of a link 23 having its opposite end attached to a pin or stud 24 depending from or connected with the work-clamp baseplate 6. The lateral or shifting movements of the work-clamp are derived from a oamgroove 25 in the feed-wheel 17 through a shifting lever 26 having at its rear end a pin .or roller-stud 27 entering said cam-groove and at its forward end a pivotal connection 28 with the transverse plate or slide 7. The shifting lever 26 swings on an adjustable fulcrum block 29 of well-known form.

As herein represented, the machine is provided with the usual fast and loose pulleys 30 and 31 mounted upon the main-shaft, and with the stopping cam 32 which is also fixed upon the main-shaft and cooperates with the spring-pressed plunger-rod 33 slidably mounted in the tilting stop-motion lever 34 fulcrumed at 35 and having a lateral arm 36 to which is pivotally connected the upper end of the treadle-rod 37 adapted to be locked in its lower position by the spring-pressed latch-arm 38 of the tripping lever 39 adapted for engagement by a tripping point on the feed-cam in a manner well-known to release the treadle-rod 37 and permit the spring-pressed stop motion lever 34 to assume operative relation with the stopping cam 32. In practice the top-motion lever 34 carries a belt-shifter for shifting the driving belt from the fast to the loose pulley when the plunger-rod 33 is brought into operative relation with the stopping cam 32.

As in the machine forming the subject of the Patent No. 806,231, the present machine is provided with needle frame vibrating means comprising the swinging lever 40 to which is adjustably connected one end of a link 41 whose opposite end is connected with a lateral arm 42 of the needle-bar frome 5. To. the lever 40 is also pivotally connected one end of the link-bar 43 which has a reciprocating motion to produce the lateral movements of the needle and has also sidewise movements imparted in one direction by the cam-actuated shifting lever 44 having a pawl member 45 periodically engaging and releasing said link-bar,which is moved in the opposite direction by means of the spring 46. As described in the said Patent No. 806,231, the lateral position of the link-bar 43 in relation to its actuating member determines the length of endwise movement of the same and thus the amplitude of needle vibrations for the said stitching and barring operations in the stitching of a buttonhole.

The machine is shown provided with a buttonhole cutting knife 47 fixed in the lower end of a knife-bar 48 having operative connections, including the rock-levers 49 and 50, with the main-shaft as described in the United States Patent No. 815,501 before mentioned. The machine is provided with a take-up lever 51 of the Singer link type, represented in the United States patent to Philip Diehl No. 462,398, dated November 3, 1891, and with the uniformly acting tension device 52 arranged below the same upon the depending head of the bracket-arm.

Upon the cap-plate 53 of the housing for the barring mechanism on the bracket-arm 2 is a stud 54 carrying a pair of tension disks 55 normally pressed together by means of the spring 56, but adapted to be separated by the shifting of the link-bar 43 for the barring operation. Arranged upon said cap-plate 53 is a second shouldered stud 57 to which are applied a pair of tension disks 58 normally pressed together by means of a spring 59 interposed between the upper disk and a nut 60 applied to the reduced threaded upper end of said stud. The upper portion of the vertical shaft 61 upon the bottom of which the feed-cam 17 is fixed is provided with a cam 62 having two substantially semicircular portions with abrupt shoulders at the opposite ends against which is adapted to rest the roller-stud 63 carried by an arm 64 fixed upon the lower end of a rock-shaft 65 having its lower portion journaled in the bearing brackets 66 secured to the bracketarm and its upper portion journaled in a bearing plate 67 shown herein secured upon the top of the cap-plate 63 and fixed from endwise movement in said bearing plate by means of the collars 68 and 69 secured thereon. As herein represented, the upper end of the rock-shaft 65 terminates in a lateral arm 70 having a wedge-shaped outer portion 71 disposed at the level of the adjacent faces of the tension disks 58, and adapted when the shaft 65 is rocked to enter the opening between their outer edges and separate the disks to release the thread lying between them. The outer end of the arm 64 carrying the roller-stud 63 is maintained yieldingly in engagement with the cam 62 by means of the spring 72 encircling the rock-shaft 65 and having one end connected with the fixed collar 68 and the opposite end attached to the bearing lug of the bracket 66.

In threading the machine, the thread a is lead under the thread guiding hook 73 between the tension disks 58, through the guide-eye 74, between the tension disks 55 and through the guide-eye 75 and thence over the guide-pin 76 to the uniform tension 52, upwardly through the eye of the take-up 51 and thence downwardly to the eye of the needle. As will be observed, the take-up is disposed as usual between the needle-eye and the several tension devices.

The so-called uniform tension device 52, as the term implies, imposes a constant tension upon the needle-thread which, in the present machine, corresponds with that upon the lower thread so that when acting alone upon the thread while the lead of the latter is directly from the needle-eye to the work the interlock of the upper and lower threads is located between the upper and lower faces of the material.

The tension device 55 acts continuously upon the needle-thread during the stitching of both sides of the buttonhole, but is released, as previously described, for the production of the bar-stitches at the opposite ends of the buttonhole.

The tension disks 58 are maintained closed, as indicated in Fig. 5, during the stitching of the first side of the buttonhole, when the lead of the needle-thread is from the needle-eye around the needle to the work as represented in Fig. 7, but at the completion of the first side-stitching operation the disks are forced apart by the implement 7O 71, as represented in Figs. 1 and 1, so that this intermittent tension device becomes in itself inoperative in the control of the needle-thread.

The initial positions of the several operative members of the machine are as represented in Fig. 1, the stop-motion lever 34 being represented as thrown forwardly to start the machine. The buttonhole having been cut, and a few tie-stitches or initial sidestitches having been formed, the roller-stud 63 is permitted to drop from the outer to the inner concentric portion of the cam 62 to cause the spring 72 to withdraw the implement 71 and allow the tension disks to close upon the needle-thread a. At the completion of the stitching of the first side of the buttonhole the roller-stud 63 rides up the inclined shoulder at the end of the inner portion of the cam-edge and causes the implement 7O 71 to engage and open the tension disks 58 to release the needle-thread a. Immediately thereafter the link-bar 4:3 is shifted and the tension disks 58 are opened for the barring operation, during which the feed-cam 17 remains stationary. At the completion of the barring operation the tension disks 56 resume their action upon the needle-thread and the continued rotation of the cam 17 causes the return feed of the work during which the lead of the needle-thread is directly from the needle-eye to the work as represented in Fig. 6, the tension disks 58 remaining open. Upon the completion of the barring operation at the end of the second side-stitching operation, the tension disks 56 having been opened for such stage of the operation, the stop-motion lever 34 is thrown backwardly to bring the plunger-rod 33 into operative relation with the stopping cam 32 and the machine comes to rest in the position of the parts represented in Fig. 1.

It will be observed that, in its relation to the present improvement, the feed-cam may be regarded as composed of two distinct parts,-viz., (a) the primary spiral camgrooved portion at one side of the camwheel supporting shaft for imparting the initial longitudinal feeding movements to the work, and (b) the device for producing the lateral shift of the work combined with the oppositely disposed secondary spiral cam-grooved portion together acting to change and finally reverse the direction of motion of the work and to impart thereto a longitudinal feeding movement in the opposite direction. It is obviously immaterial whether or not these practically independent successively acting parts of the cam-wheel be formed integral in a single member, so long as they act in succession to perform the described initial feeding movement in one direction and then a change in the original direction of motion and a movement of the work in another direction relative to the stitch-forming mechanism.

The automatically controlled tension 56 has no necessary operative connection with the primary feeding device, as regards its control in the proper setting of the stitches, but its operative connection with the secondary feeding or feed-direction-changing device is important inasmuch as the action of the tension upon the thread mustbe established and interrupted respectively at the beginning and conclusion of operation of the direction-changing device to produce the uniform stitching which the present inven tion is designed to accomplish.

From the foregoing description it will be observed that according to the present improvement the means for controlling the thread in its passage to the needle acts differently under changes of direction of feed so as to compensate for varying conditions in the lead of the thread from the needleeye to the work; and therefore the action of the thread-controlling devices for different directions of feed of the work differs in scope, rather than in timing, in the production of successive stitches, the controlling action being uniform during the production of all stitches produced in the same direction of feed.

From the foregoing description it will be seen that the present improvement is adapted for embodiment in all classes of sewing machines in which the lead of the thread from the-needle-eye is caused to vary in direction from its point of connection with the work rearwardly of the needle and in a direct line from its point of emergence from the needle-eye into a direction in advance of such point of emergence, whereby the thread is bent or wrapped around the blade of the needle in its passage to the work. As the characteristic feature of the improvement is the variation in the control of the needle-thread to correspond with the different resistances offered by the needle to passage of the same by reason of changes in its direction of lead from the needle-eye to the work, it is evidently immaterial to the invention, in its broader aspect, what one of the known means of thread control is employed in the handling of the needlethread, so long as means are provided for varying its action to compensate for the varied resistances imposed by changes of lead of the thread in the relative movements of the stitch-forming devices and the work. i

It will be observed that, so long as the lead of the thread from the needle-eye is rearward, or in a direction back of a plane through the center of the needle transverse to its eye, and the lead of the thread to the ,the thread to the setting of stitch is materially' increased, and the pull upon the thread in setting the stitch must necessarily be increased to insure uniform stitching.

In the appended claims, the expressions forward and rearward, as used to indicate'the lead of the thread from the needleeye, are to be understood in relation to the position of the point of connection of the thread to the work relative to the said transverse plane, although as applied to buttonhole machines the change of direction involving the described change in condition of the thread-controlling device is an actual reversal of the direction of feed.

Having thus set forth'the nature of the invention, what I claim herein is 1. In a sewing machine, the combination with stitch-forming mechanism comprising a thread-carrying needle and means for imparting operative movements thereto, and work-feeding mechanism including a workengaging member a controlling shaft and an operative connection between said shaft and the work-engaging member whereby changes in the direction of feed are produced, of a needle-thread tension device adapted for normal uniform action upon the thread in the production of a succession of stitches, and means including a cam on the feed-controlling shaft acting through connections independent of the needle-operating means and the feed-actuating connections for changing the intensity of action of the tension upon the needle-thread intermediate the production of different successions of stitches.

2. In a sewing machine, the combination with stitch-forming mechanism comprising a reciprocating needle and means including a rotary feed-cam for producing relative to-and-fro feeding movements in opposite directions between the stitch-forming mechanism and the work, of a tension device, and controlling means therefor including a cam-member rotating with said feed-cam and alternately active and inactive upon said tension device during the operation of the feed-cam in imparting respectively a relative initial and retrograde feeding movement.

3. In a sewing machine, the combination with stitch-forming mechanism comprising a reciprocating needle and means including a feed-cam for producing relative feeding movements in different directions between the stitch-forming mechanism and the work, of a tension device, and controlling means therefor including a cam member permanently connected to and movable with said feed-cam and connections between said cam member and the tension device whereby the action of the latter upon the thread is changed correspondingly with changes in the direction of feed between the stitchforming mechanism and the work.

4. In a sewing machine, the combination with stitclrforming mechanism comprising a reciprocating needle and means including a feed-cam for producing relative to-andfro feeding movements in opposite directions between the stitch-forming mechanism and the work, of a tension device comprising a pair of spring-closed tension disks, an implement adapted to separate said tension disks to release the thread, a cam-shaft upon which the feed-cam is mounted, and a cam member fixed upon said feed-cam shaft and connected with said implement whereby said disks are caused to be separated when the relative feed of the work is effected in one direction and said disks are caused to remain closed when such feed is effected in the opposite direction.

5. In a sewing machine, the combination with stitch-forming mechanism comprising a reciprocating needle and means including a feed-cam for producing relative to-andfro feeding movements in opposite directions between the stitch-forming mechanism and the Work, of a tension device comprising a pair of spring-closed tension disks, a cam member movable With said feed-cam, a rock-shaft, a lateral arm fixed thereon and carrying a roller-stud adapted to engage said cam member, and a lateral arm upon said rock-shaft adapted to enter between said tension disks to separate them for the release of the thread.

6. In a buttonhole stitching machine, the combination With stitch-forming mechanism comprising a reciprocating needle, a travel ing Work-holder, and a feed-cam adapted to impart to the Work-holder feeding movements in opposite directions, of a uniform tension device, a takeup, intermittent tension mechanism, and controlling means for said intermittent tension device comprising a cam connected With the feed-cam and adapted to cause the said intermittent tension device to act upon the thread during the feed of the Work-holder in one direction and to remain inactive upon the thread during the feed of the Work-holder in the opposite direction.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

LESTER LE ROY ALMOND.

Witnesses:

IRENE E. TRIMBLE, RANSOM H. GILLET.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

